1. Field of the Invention
The invention relates to a wafer handling checker for checking up an operation state of a semiconductor wafer.
2. Description of Related Art
An operation training of wafers in fabrication of semiconductor devices has been generally conventionally performed in the manner that genuine wafers housed in each slot of a cassette are transferred by an operator to be trained (hereinafter referred to as trainee) and the surfaces of the transferred wafers are inspected, thereby checking up the increased number of defects such as flaw and the like to measure the degree of advancement of the operation.
However, according to the conventional method of operation training of wafers, it was necessary that the number of defects of the wafers is inspected before the operation of the wafers, and the number of defects of the wafers was inspected again after the operation of the wafers, thereby checking up the number of defects which was increased during the operation of the wafers. Accordingly, there were problems that not only an enormous quantity of work and time were required for inspecting the wafers but also a material cost increased because it was difficult to recycle the wafers which suffered big damages, and hence such damaged wafers had to be disposed of.